Secondary Air Injection System Switching Valve A Stuck Open
The secondary air injection valve A is stuck in the open position.
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What it means (plain English)
The system that helps reduce emissions is trying to work, but one of the valves is stuck open, which can cause too much air to flow where it shouldn't be.
What the computer is actually seeing
The PCM detects that the secondary air injection system's switching valve A is always reading as open, indicating a stuck condition, through inputs from the engine sensors.
What a healthy reading looks like
When testing the valve, it should show a zero voltage (closed) when not activated and a voltage around 12V when activated. The expected flow rate into the exhaust should be between 1-5 liters/minute under operation.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect the wiring and connector to the secondary air injection valve A for damage or corrosion. Decision: If damaged, repair/replace. If good, move to step 2.
- 22. Check the operation of the secondary air injection valve A using a scan tool to command the valve open and closed. Decision: If it does not respond, replace the valve and retest. If it works, move to step 3.
- 33. Test the voltage at the valve connector with the key on, engine off. Expect around 12V. Decision: If low or no voltage, check for blown fuses and PCM output. If voltage is correct, move to step 4.
- 44. Inspect for vacuum leaks in the air injection system. Use a smoke tester if necessary. Decision: If leaks are found, repair leaks and retest. If no leaks, consider the PCM.
Common causes
- Faulty secondary air injection valve A
- Wiring or connector issues leading to improper readings
- Vacuum leak causing excessive air flow
- PCM software issues
Typical repair cost
$$$-$$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's best to repair this soon as it can affect emissions and fuel efficiency, but you may still drive it temporarily.
Will this code come back after clearing it?
If the underlying issue isn't fixed, yes, it will likely return.
Why does this code appear with other codes?
Related codes often indicate problems in the same system, such as the air injection system or electrical issues.
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